Seeing as how a lot of wood split easily in the movies and videos online, I think those are dry/dried ones already. Yours is not only fresh, but had a lot of water inside them. If it was already hard work with the machine, I wonder how traditional wood cutters would deal with it. I guess they might let it dry first before even trying.
They would normally cut the wood in the autumn or winter when there is no water running through the trees, then pile them and leave them in the forest to dry. Only after that would they cut them like this.